1. Field of the Invention
The present invention relates to power plants. More specifically, the present invention relates to methods and apparatus for a very low polluting power plant having a liquid fuel combustion chamber for the burning of hydrocarbon based fuels.
While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility.
2. Description of the Related Art
Many different types of liquid fueled power plants are known in the art for providing thrust for propulsion, power generation and other applications. Examples include liquid fueled jet engines, piston engines and rocket motors of various designs. Conventional liquid fueled power plant designs tend to suffer from a number of problems not the least of which is the generation of excessive heat and noise. Also, in the case of a conventional liquid fueled rocket motor, a considerable amount of smoke can be generated which results in increased levels of atmospheric pollution.
In any event, the generation of excessive heat, noise and smoke during the launch and flight stages increases the probability that the projectile will be detected on approach. As the projectile becomes detectable, the launch point becomes detectable as well. Likewise, when driving a generator with, for example, a liquid fueled piston engine, the smoke exhaust from the engine increases the atmospheric pollution level.
Specific examples of liquid fueled power plant designs capable of providing thrust to propel a projectile include a liquid fueled turbine jet engine and a liquid fueled ramrocket motor. Turbine jet engines employing liquid fuel are known and are capable of providing thrust to propel a projectile and to provide rotational power to ground based power generator plants. In general, a turbine jet engine has a long cylindrical body and includes one or more liquid fuel burning chambers. The burning chamber is located at the center of the long cylindrical body and normally burns at temperatures in excess of three-thousand degrees Fahrenheit. The turbine jet engine includes multiple compression stages which produces a very high pressure in the burning chamber. When the liquid fuel is injected into the burning chamber, the fuel is combusted to provide hot, high pressure gases and enormous output horsepower.
The outer walls of the burning chamber are at a lower temperature than that of the flame at the center of the burning chamber. Because of the temperature differential between the flame and the outer wall and the operating temperature of the burning chamber, the liquid fuel is not totally combusted. The liquid fuel is generally a hydrocarbon based fuel. When particles of a hydrocarbon based fuel are not totally burned, hydrocarbon based pollutants are produced. Further, since all of the liquid fuel is not totally combusted, the turbine jet engine is not fuel efficient. Additionally, the turbine jet engine is very noisy and produces excessive heat. Each of these characteristics of turbine jet engines increases the detectability of a projectile and the pollution level of the atmosphere.
The second example of a known liquid fueled power plant design capable of providing thrust to propel a projectile is a ramrocket motor. The ramrocket motor is a hybrid rocket motor generally having a short motor casing. The length of the motor casing is approximately three times the diameter of the rocket motor combustion chamber. The ramrocket motor burns liquid fuel which is injected into the combustion chamber along with compressed ambient air. The output of the combustion chamber is a hot pressurized gas which is directed to an impulse turbine blade that rotates a propeller or ducted fan. Ramrocket motors are normally utilized with air breathing missiles or any application that utilizes hot pressurized gas.
The combustion chamber of the ramrocket motor includes a device that provides a flame at the center of the rocket motor. Thus, the center of a ramrocket motor also operates at a temperature in excess of three-thousand degrees Fahrenheit. A high volume of air is forced through the rocket motor causing the temperature of the outer wall of the combustion chamber to be lower than the temperature at the center of the combustion chamber. The temperature differential between the center and the outer wall of the rocket motor results in incomplete combustion of some liquid fuel drops. This condition produces hydrocarbon and carbon pollution which is exhausted to the atmosphere. Therefore, liquid fueled rocket motors must be preheated to a specific temperature range to ensure total combustion of the fuel. Otherwise, a fuel efficiency problem results.
Further, the desired combustion temperature range of operation within the ramrocket motor is difficult to control. If the desired combustion temperature range is not maintained, the flame at the center of the combustion chamber is extinguished because of the length-to-diameter ratio of the motor casing. Further, ramrocket motors must be operated very hot and fuel rich to avoid extinguishing of the combustion chamber flame. This situation results in fuel waste. Additionally, if the liquid fuel and compressed air are not properly mixed, residue smoke in the form of carbon particles appears in the exhaust gases. The smoke residue permits the projectile to be optically tracked. Finally, the ramrocket motor is very noisy which permits the projectile to be tracked by an audible sensor. Each of these characteristics of ramrocket motors increases the detectability of the projectile and the pollution level of the atmosphere.
A final example of a liquid fuel power plant design of the prior art is an incinerator employed for destroying hazardous waste. The incinerator includes a cylindrical combustion chamber joined by a flat circular plate to a smaller inlet pipe. Fuel nozzles protrude through the flat plate into the combustion chamber. The air and fuel are not premixed but rather are injected into the combustion chamber at the point of flame stabilization. Total combustion of the fuel occurs and low nitrous oxide (NO.sub.x) levels are produced. Recirculation of the gas and air mixture is employed to ensure total combustion. The heat generated by the combustion is released to the atmosphere through a long hot exhaust tube that completes the decomposition of the hydrocarbon and carbon molecules.
Thus, there is a need in the art for improvements in the design of liquid fueled power plants to reduce the detectability of and the exhausted pollutants from the power plants.